I recently asked my husband why using NFP to avoid pregnancy sometimes feels so much less certain than using a contraceptive.

At first he said that it was because when a couple uses NFP they aren't actually doing anything to avoid pregnancy.

Then, a moment later, he said, "No, that's not right. It's because with NFP we have to do everything."

"Huh?" I said. But then I understood.

We are constantly told - by the media, by most of the medical profession, by the echo of our high school "health" teachers - that in order for sex to be "safe" we have to use some thing. We can take a pill, erect a barrier, put ourselves under the surgeon's knife, but somehow we must "protect" ourselves.

Statistically, NFP is as effective as hormonal contraceptives like the pill and couples with truly serious reasons to avoid pregnancy almost never become pregnant while using NFP. There is, however, a tremendous difference in the level of responsibility NFP users must assume.

There is a great temptation for couples who use contraception to tell themselves that conception cannot happen that because they are being "responsible" and making use of a drug, device or surgical procedure, they absolutely cannot become pregnant.

This is, of course, a lie.

It is simply not possible for a man and woman who both have all of their reproductive organs to have sex without there being some chance, even if it is very small, that a child will be conceived.

One sometimes sees this temptation played out when a couple who has used NFP in the past comes to a point in their marriage where they unexpectedly have very serious reasons to avoid another pregnancy. Rather than trust their knowledge of and experience with NFP, in their fear (and often at the urging of friends and medical professionals) these couples will sometimes abandon NFP and begin using a method of contraception with which it is actually far more likely that they will conceive unintentionally.

A couple who use NFP cannot cling to the (mistaken) belief that a drug or device will "protect" them from pregnancy. The responsibility for avoiding conception is squarely on their shoulders . . . and in God's hands.

When a couple who uses NFP does experience an unplanned pregnancy, then, it is due to one of two things; either the couple themselves did not follow the rules for avoiding pregnancy or God "our Lord and creator" intervened.

Those who have obviously very grave reasons to avoid conception are extremely conscientious about learning and practicing NFP properly and true surprise pregnancies (those that occur despite a couple correctly understanding and faithfully following the rules for avoiding pregnancy) are so exceptionally rare that when they do occur they can honestly be considered little miracles. With NFP, however, there is no third party - no device manufacturer, no pharmaceutical company, no surgeon - to take the blame. There are only ourselves and our God and that is exactly as it should be.

The challenge for all of us, and particularly for those who are struggling to trust NFP, is to recognize the truth that God who is Lord of heaven and earth is also the Lord of our families and of our fertility and that His admonition to "fear not" applies here too.

Source: Sara Fox Peterson www.catholicmom.orgSara Fox Peterson is a stay-at-home mom and certified teacher of the Billings Ovulation Method of Natural Family Planning. She holds a BS in biology and an MS in human physiology, both from Georgetown University